Box elder bugs are everywhere in Southern Ontario, but what exactly are they doing on your trees and plants all summer? Understanding their diet is key to understanding why they love your property so much.
The box elder bug ($*Leptocoris trivittatus*$) is a “true bug,” meaning it has piercing-sucking mouthparts that it uses to feed on plant liquids. But what’s their preferred meal?
The Preferred Feast: Maple Seeds
Box elder bugs get their common name from their favourite food source: the Box Elder tree (Acer negundo), which is also known as the Manitoba Maple.
- Seed Eaters: Their primary food is the fallen seeds of the female Box Elder tree. The seeds are highly nutritious, and the nymphs (young bugs) are often found feeding on them on the ground throughout the summer.
- Sap Suckers: They also use their mouthparts to extract sap from the developing seed pods, leaves, and tender twigs of the Box Elder tree.
Other Occasional Snacks
While Box Elder trees are their top pick, they are known to feed on other nearby vegetation, particularly other members of the maple family:
- Maple Trees: They will sometimes feed on the leaves and seeds of other maple species, such as silver maple.
- Ash Trees: Ash trees can also serve as a host plant.
- Fruit Trees: Occasionally, they may feed on the fruit of plum, cherry, peach, or apple trees, which can cause minor dimpling or scarring on the fruit’s surface.
Do They Harm My Plants?
The good news is, no. While a large infestation can cause some speckling or distortion on tree leaves, the damage caused by box elder bugs is almost always insignificant and cosmetic.
For the vast majority of homeowners, the only real concern is not the damage to the plants, but the nuisance of the bugs trying to move indoors to find warmth in the late summer and fall.